Digital mammography finds more breast cancers

The switch from film mammography to digital mammography has led to an increase in breast cancer detection rates, researchers from California report.

According to Drs. Fred S. Vernacchia and Zachary G. Pena, of the San Luis Diagnostic Center, San Luis Obispo, up to 70 percent of screening facilities in the US are still using film-screen mammography.

Based on their experience, Vernacchia said, "I would certainly encourage patients...to look for facilities that have digital technology."

Conventional mammography involves the creation of a breast image directly onto film. With digital mammography, by contrast, an electronic image is taken and stored in a computer. The display characteristics of the image can then be manipulated and the radiologist can use software to help detect breast abnormalities.

Vernacchia and Pena analyzed data on 4838 mammography screenings done in the year before they converted to digital mammography and on more than 21,500 screenings done over the subsequent 3 years.

They found that there was a significant increase in the number of breast cancers detected following the switch from film-screen to digital mammography.

The number of cancers detected prior to the switch averaged between 4.1 to 4.5 cancers per 1,000 women imaged. Following the switch, the cancer detection rate increased to 7.9 cancers per 1,000 women imaged and has remained high.

"It is clear, at least to me," Vernacchia told Reuters Health, "that there exists a clinical superiority of digital over film-screen mammography."

"I am hoping," he concluded, "that as more facilities convert from film-screen to digital, they will share their results with the rest of the medical community."

SOURCE: American Journal of Roentgenology, August 2009.